“Furious parents and health care professionals in China are demanding to know how almost $90 million of improperly stored and potentially fatal vaccines were distributed across some two-thirds of the country over the past five years, in the latest public-health scandal to raise serious questions over the efficacy of the Chinese Communist Party’s rule.

“According to state media, a mother and daughter from eastern China’s Shandong province have been caught peddling 25 kinds of unrefrigerated vaccines — including for polio, mumps, rabies, hepatitis B, encephalitis and meningococcal diseases — to medical facilities across 24 Chinese provinces since 2010.

“Inflaming the public backlash, authorities had apparently known about the case since last April, though only publicized the news late Friday in a belated attempt to trace potential victims. Moreover, the elder suspect, a 47-year-old woman surnamed Pang, had apparently been convicted of the same offense in 2009 but only received a suspended sentence. State media admitted the compromised inoculations could have resulted in paralysis and even death.